Rosin ester-based compositions and applications thereof

Abstract

Rosin ester-based compositions are disclosed comprising (a) at least one polymer and (b) a rosin ester formed by esterification of a rosin or rosin acid with a cyclic polyol. The cyclic polyol is defined by a carbon-to-oxygen ratio of 1.0 to 20 and < 5 rotatable carbon– carbon bonds, thereby providing enhanced rigidity and compatibility. The resulting rosin ester can be employed directly without further modification and exhibits advantageous performance in polymer systems. Applications include hot-melt and pressure-sensitive adhesives, tire and rubber compositions based on diene rubbers, and other polymer-based materials requiring improved thermal stability, clarity, and adhesion balance.

Description

ROSIN ESTER-BASED COMPOSITIONS AND APPLICATIONS THEREOFRELATED APPLICATIONS

[0001] This application claims benefit to US Provisional Application No. 63 / 697,681, filed on September 23, 2024, which is incorporated herein by reference.FIELD

[0002] The disclosure relates to a rosin ester-based composition containing a rosin ester made with a cyclic polyol, methods of preparation, and applications thereof.BACKGROUND

[0003] Rosin esters are widely used in a variety of industrial and consumer applications, including adhesive compositions, inks, coatings, tires, personal care products, road markings, textile finishing, agricultural formulations, and fuel additives. In many of these applications, rosin esters are incorporated into adhesive compositions as tackifying agents in combination with a polymer. For an adhesive composition to perform reliably, the components should be compatible with one another and remain free of phase separation, both at ambient conditions and at elevated temperatures typically used during application.

[0004] Increasing attention has been directed to the use of raw materials derived from renewable resources, which can reduce dependence on petroleum-based feedstocks and provide biodegradability or, in some cases, industrial compostability. To be suitable for use in adhesive compositions, such renewable components must exhibit compatibility with conventional adhesive polymers. For example, adhesive compositions are frequently formulated with ethylene-vinyl acetate (EVA), metallocene-catalyzed polyolefins (mPOs) or amorphous polyolefins (APOs). Conventional rosin esters have sometimes been modified with aliphatic monomers to improve their compatibility with these polyolefin polymers.

[0005] There is still a need for rosin esters that are compatible with various polymer components, for use in multiple applications.SUMMARY

[0006] In one aspect, the disclosure relates to a rosin ester obtained by reacting a rosin with a cyclic polyol. The rosin ester is characterized as having an acid number of < 50 mg / KOH / g, preferably < 40 mg / KOH / g; more preferably < 30 mg / KOH / g; a weight average molecular weight of < 6,000 g / mol, preferably < 5000 g / mol, more preferably < 4000g / mol;and a glass transition temperature (Tg) of -80 to 100°C measured according to ASTM D 6604. In one aspect, the cyclic polyol is selected from tricyclodecanedimethanol (TCDM), cyclohexanedimethanol (CHDM), dianhydrohexitols (isosorbide, isomannide, isoidide), cyclohexanediol, spiroglycol, phloroglucinol, inositol, quinic acid, and mixtures thereof. The cyclic polyol has a carbon-to-oxygen atom ratio of 1.0-20, or 1.5 - 15; and <5 rotatable C-C bonds (preferably <3; more preferably <2).

[0007] In a second aspect, the rosin ester is characterized as being compatible with ethylene-vinyl acetate copolymers, metallocene-catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a-olefin plastomers, amorphous poly-a-olefins, wherein a 1 : 1 (w / w) blend with any of these polymers remains free of visible phase separation after 24 hours at 160 °C in the Compatibility Test Method.

[0008] In third aspect, the rosin ester is characterized as being compatible with ethylene-vinyl acetate copolymers, metallocene-catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a-olefin plastomers, amorphous poly-a-olefins, wherein a 1 : 1 (w / w) blend with any of these polymers exhibits a cloud point < 150 °C (80 % transmission) in the Cloud Point Compatibility Test Method.

[0009] In another aspect, an adhesive composition is disclosed. The adhesive comprises: 10-60 wt.% of the rosin ester as previously described, 20-70 wt.% of a polymer selected from the group consisting of ethylene-vinyl acetate copolymers, metallocene- catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a-olefin plastomers, and amorphous poly-a-olefins, and 0-40 wt.% of a plasticizer. The adhesive exhibits a cloud point of less than 160 °C determined in accordance with ASTM D6045 (polymer-rosin blend turbidity method, and a melt viscosity at 180 °C of less than 50,000 mPa.s measured by a Brookfield rotational viscometer with Thermosel heater in accordance with ASTM D3236.DETAILED DESCRIPTION

[0010] The following terms will have the following meanings:

[0011] “Consisting essentially of’ means that the claimed composition primarily contains the specified materials, with allowances for additional components that do not materially affect novel characteristics or function of the claimed invention, with the additional components, if present, in an amount of < 30%, or < 20%, or < 10%.

[0012] “At least one of [a group such as A, B, and C]” or “any of [a group such as A, B, and C]” means a single member from the group, more than one member from the group, or a combination of members from the group. For example, at least one of A, B, and Cincludes, for example, A only, B only, or C only, as well as A and B, A and C, B and C; or A, B, and C, or any other combinations of A, B, and C.

[0013] A list of embodiments presented as “A, B, or C” is to be interpreted as including the embodiments, A only, B only, C only, “A or B,” “A or C,” “B or C,” or “A, B, or C ”

[0014] "Any of A, B, or C" refers to one option from A, B, or C, e.g., A only, B only, or C only.

[0015] "Any of A, B, and C" refers to one or more options from A, B, and C, e.g., A only, B only, C only, A and B, A and C, A and B and C, etc.

[0016] “Molecular weight” or Mw refers to the polystyrene equivalent molecular weight in g / mol of a polymer block or a block copolymer. Mw can be measured with gel permeation chromatography (GPC) using polystyrene calibration standards, such as is done according to ASTM 5296. The GPC detector can be an ultraviolet or refractive index detector or a combination thereof. The chromatograph is calibrated using commercially available polystyrene molecular weight standards. Mw of polymers measured using GPC so calibrated are polystyrene equivalent molecular weights or apparent molecular weights. Mw expressed herein is measured at the peak of the GPC trace and is commonly referred to as polystyrene equivalent “peak molecular weight,” designated as Mp.

[0017] “Acid value” or “neutralization number” or “acid number” or “acidity” used interchangeably and measured according to ASTM D465-05 (2010).

[0018] “Gardner color scale” refers to a scale used to measure intensities of yellow color for liquid samples. Lighter (i.e., less) yellow intensity corresponds to a lower Gardner color value.

[0019] “PAN number” refers to the sum of the weight percentages of palustric, abietic and neoabietic acid moieties as obtained by hydrolysis from the rosin ester.

[0020] “Oxygen content” refers to the weight percentage of oxygen atoms relative to the total molecular weight of the compound, as determined byA13C NMR or elemental analysis.

[0021] “Elastomer” is used interchangeably with the term “rubber,” referring to any polymer or combination of polymers consistent with ASTM DI 566 definition.

[0022] “Phr” refers to parts by weight per hundred parts of elastomer / rubber (of the sum of the elastomers if several elastomers / rubbers are present).

[0023] "Long chain branching” or LCB refers to the presence of extended side chains or branches along a polymer backbone, expressed as number of LCBs per 1,000,000 carbons, LCB / 106carbons, as measured using GPC and / or NMR techniques.

[0024] “Short chain branching” or SCB refers to the presence of shorter side chains or branches attached to a polymer backbone. These branches are composed of a smaller number of repeat units compared to the polymer backbone. SCB occurs when a comonomer, e.g., 1- butene, is copolymerized with the main olefin monomer e.g., ethylene. The comonomer units disrupt the regularity of the polymer backbone, introducing branches at relatively regular intervals. The main difference between LCB and SCB is that in LCB, long chain branches consist of multiple repeat units and are relatively longer, e.g., more than a few dozen (> 36) to several thousand repeat units in length. A few here means “3” as a unit. In contrast, in SCB, short chain branches are shorter in length or smaller number of repeat units, e.g., a few to a few dozens, e.g., 2, 5, 10, 20, 30, < 36 of repeat units. The SCB can be measured using the GPC-IR method.

[0025] “Rotatable carbon-carbon bonds” refers to single bonds between two carbon atoms that can undergo free rotation about the bond axis, excluding double bonds, bonds to sp2-hybridized carbons, and bonds that are part of a ring structure.

[0026] “Compatible” refers to a polymer and rosin ester combination that remains free of visible phase separation under static heating. Compatibility can be determined by ‘Compatibility Test Method’. In this test, a blend of the rosin ester and the polymer (typically 1 : 1 by weight unless otherwise specified) is heated to a processing temperature within 100- 200 °C (selected to correspond to the intended use of the composition), held 24 hours, and then examined with the naked eye against a black / white background. If no visible phase separation is observed after 24 hours, the polymer and rosin ester are deemed compatible under these conditions. Compatibility can also be determined by a ‘Cloud Point Compatibility Test Method.’ This method is analogous in principle to ASTM D7638-20 but adapted for polymer / rosin ester blends. In this test, a 1 : 1 (w / w) blend of the rosin ester and polymer is heated to 180-200 °C under agitation until a homogeneous, transparent melt is obtained. The melt is then cooled from 200 °C to 25 °C at ~2 °C / min while optical clarity is monitored (visually or, when instrumented, at a defined light-transmission threshold, e.g., 80% T). The cloud point is the temperature at which haze, or turbidity is first observed upon cooling. Lower cloud points indicate greater compatibility of the rosin ester with the polymer.

[0027] “New Carbon Content Test Method” refers to ASTM D6866-22 Method B (AMS), entitled “Standard Test Methods for Determining the Biobased Content of Solid,Liquid, and Gaseous Samples Using Radiocarbon Analysis.” The method determines the percentage of biogenic carbon in a sample based on radiocarbon (A14C) analysis, reported as % biogenic carbon relative to the total carbon content of the sample.

[0028] “Rosin Ester-Based Composition” refers to a composition containing the rosin ester disclosed herein and a polymer.

[0029] The disclosure relates to a composition comprising a rosin ester obtained as a reaction product of a rosin and a cyclic polyol. The rosin ester is characterized as being compatible with a number of polymers, suitable for use in many applications including hot- melt adhesives and tires.

[0030] (Rosin Esters): The rosin ester-based composition comprises a rosin ester, obtained by reacting a rosin (rosin acid) with a cyclic polyol, and in embodiments without the need for additional modification to the rosin ester.

[0031] Rosin Feedstock: The rosin here refers to rosin acid. In embodiments, the rosin includes a mixture of rosin acids, with the composition of the rosin varying depending on the plant species. Rosin acids are C20 fused-ring monocarboxylic acids, e.g., abietic acid, neoabietic acid, dehydroabietic acid (DHA), dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid, and palustric acid. Rosin can be obtained from any of gum rosin, wood rosin, and tall oil rosin. Tall oil rosin (TOR) typically has a higher proportion of pimarane-type acids (e.g., isopimaric, sandaracopimaric) compared with gum rosin, which can affect ester softening point and compatibility.

[0032] In embodiments, the rosin is a gum rosin, which is used as a base material to make rosin ester derivatives. Gum rosin can undergo esterification with polyols to form a rosin ester. Chemically, gum rosin is composed of resin acids such as abietic acid, neoabietic acid, palustric acid, and levopimaric acid. The melting point of gum rosin ranges from 75 to 95°C. In embodiments, the gum rosin has a resin acid content of 70-90 %, or 65-98%, or > 65 %, or < 98%, depending on the specific formulation.

[0033] In embodiments, the rosin is a hydrogenated rosin. Hydrogenation may be partial or extensive and is evidenced by a lower iodine value, decreased UV absorbance in the 240-300 nm region, and diminished olefinic signals by FTIR / NMR. In some embodiments, the residual residual C=C double bonds ranges from < 20%, or < 15%, or < 10%, or < 5%, or > 1%. In embodiments, the remaining C=C double bonds range between 1% - 20% or 1% - 10%, calculated based on the total initial double bond content. Hydrogenation generally lightens color and improves thermal / oxi dative stability of the feedstock and the derived esters. Selection of hydrogenation level may be used to balance stability with targetedcompatibility. When hydrogenated rosin is used, the resulting rosin esters can show lower cloud points and improved blend homogeneity with certain polymers (e.g., low-VA EVA, metallocene polyolefin elastomers), relative to esters from unhydrogenated rosin. Hydrogenated rosin esters may exhibit slower heat-age yellowing, reduced viscosity growth, and longer shelf stability under storage and use conditions.

[0034] In embodiments, the rosin is disproportionated, increasing dehydroabietic and dihydroabietic acids at the expense of abietic / neoabietic species. Disproportionation typically yields improved color stability, lower iodine value, and a feedstock useful for esters requiring better thermal color.

[0035] In embodiments, the rosin is a fortified rosin. Fortification of the rosin involves chemical modification of the conjugated double bond system of rosin acids in the rosin, to provide a rosin having a lower PAN number (sum of palustric + abietic + neoabietic, wt.%, e.g., < 25, < 20, etc.) and higher molecular weight than the rosin prior to fortification. As used herein, the PAN number is the sum of the percentage of rosin acids in the rosin that are palustric acid, abietic acid, and neoabietic acid. Fortified rosin may be prepared by reaction of rosin with maleic anhydride, fumaric acid, acrylic acid, or other unsaturated carboxylic acids.

[0036] In embodiments, the rosin comprises a dehydroabietic acid in amounts of > 30, or 30 - 60, or 40 - 55 wt.%, based on total weight of the rosin. In embodiments, the rosin has a weight ratio of dehydroabietic acid to dihydroabietic acid in the range of 1 :0.80 to 1 :0.25, or 1 :0.70 to 1 :0.35, or 1 :0.55 to 1 :0.40.

[0037] In embodiments, the rosin feedstock is refined to reduce neutral components (unsaponifiables, sterols, hydrocarbons) to less than 10 wt.%, such as less than 5 wt.% or less than 2 wt.% of the total rosin.

[0038] In embodiments, the rosin has an acid number of 120 - 190, or 150 - 185, or 170 - 182 mg KOH / gram.

[0039] In embodiments, the rosin is added in amounts of 15 - 93, or 55 - 90, or 20 - 60, or 25 - 75 wt.% to prepare the rosin ester, base total weight of the reactants.

[0040] Cyclic Polyols: In embodiments, the reactant forming rosin ester is one or more cyclic polyols. Cyclic polyols contribute to the rigidity and stability of rosin esters.

[0041] In embodiments, the cyclic polyol has a general structure of any of (I), (II), (III), or (IV):

[0042] Structure (I), (II), (III), and (IV) illustrates one class of suitable cyclic polyols having pendant hydroxymethyl substituents on a cycloaliphatic ring; however, the term “cyclic polyol” as used herein also includes compounds bearing one or more ring-bound hydroxyl groups (-OH) and ring systems that are fused, bridged, or spirocyclic, and may be carbocyclic, aromatic, or heterocyclic (e.g., furan, acetal). Accordingly, cyclic polyols disclosed herein include additional functional groups (e.g., ether / acetal, lactone, or carboxylic acid) provided at least one hydroxyl group is available for esterification. Examples of such additional functionalities include ether or acetal oxygen atoms present in dianhydrohexitols, lactone groups present in quinic acid, or carboxyl groups as in quinic acid and shikimic acid.In embodiments, the cyclic polyol comprises 0-2 ring oxygen atoms in the core carbocycle.Additional oxygen atoms may be present in pendant substituents or in fused, bridged, or spirocyclic frameworks

[0043] In the structures: n > 3, or 3 < n < 12, or 3 < n < 18; each of R1-R8 is independently selected from hydrogen, hydroxyl (-OH), hydroxymethyl (-CH2OH), and carboxyl (-COOH), with R7-R8 are independently oriented a or P, at least two of R1-R8 are substituents other than hydrogen, at least one of R1-R6 is -OH or -COOH. In embodiments when n = 3, each of R’3 and R” is independently hydrogen or methyl. In embodiments when n = 4, R’3 is hydrogen.

[0044] In embodiments, the cyclic polyol is any of carbocyclic or heterocyclic, aromatic or non-aromatic.

[0045] In embodiments, the cyclic polyol has a ratio of carbon to oxygen (C / O) of > 1.0, or > 1.5, or > 2.0, or > 2.1, or > 2.2, or < 8, or 2 - 8, or 2.1 - 7.5, or 2 - 7, or 1.0-20, or 1.5 - 15.

[0046] In embodiments, the cyclic polyol has a low number of rotatable carboncarbon bonds in the cyclic ring of the core structure. The rotation is minimal due to the overall rigidity of the cyclic structure. In embodiments, a number of rotatable carbon-carbon bonds is < 5, or < 4, or <3, or < 2, or 0.

[0047] In embodiments, the cyclic polyol is selected from the group consisting of: tricyclodecane dimethanol (TCDM), cyclohexane dimethanol (CHDM), dianhydrohexitols, cyclohexanediol, spiroglycol, phloroglucinol, inositol, quinic acid, borneol, isobomeol, shikimic acid, camphoric diols, 2,5-bis(hydroxymethyl)furan (BHMF), and mixtures thereof. These cyclic polyols include both saturated and unsaturated backbones, with stereochemistry (endo / exo, cis / trans, a / p) influencing solubility and reactivity but not limiting their use herein.

[0048] In embodiments, the cyclic polyol is a tricyclodecane dimethanol (TCDM) selected from at least one of 3, 8-bis (hydroxymethyl) tricyclo [5.2.1.02'6] decane; 3, 9- bis (hydroxymethyl) tricyclo [5.2.1.02‘6] decane; 4, 8- bis (hydroxymethyl) tricyclo [5.2.1.02 "6] decane; 4, 9-bis (hydroxymethyl) tricyclo [5.2.1.02‘6] decane; 5, 8-bis (hydroxymethyl) tricyclo [5.2.1.02'6] decane; and 5, 9- bis (hydroxymethyl) tricyclo [5.2.1.02'6] decane.

[0049] In embodiments, the cyclic polyol is dianhydrohexitols. In embodiments, dianhydrohexitols are bicyclic diols obtained by double intramolecular dehydration of Ce sugar alcohols (hexitols). The dehydration forms a rigid bicyclic framework composed of two fused tetrahydrofuran rings bearing two hydroxyl groups. The three known forms areisosorbide, isomannide, and isoidide, which differ only in the stereochemical orientation of their hydroxyl substituents. Isosorbide, isomannide, and isoidide are structural isomers that share the same bicyclic G> backbone, and their stereochemical differences influence solubility, crystallinity, and reactivity.

[0050] In embodiments, the cyclic polyols have hydroxyl functionality from 2 to 10, or preferably from 2 to 7, or most preferably from 3 to 5. In embodiments, cyclic polyols have carbon atoms ranging from 2 to 36, or preferably from 2 to 20 or most preferably from 2 to 8. Hydroxyl functionality is determined by the number of reactive hydroxyl groups per molecule, as confirmed by 1H NMR and hydroxyl number titration (ASTM E222).

[0051] In embodiments, the cyclic polyol has an oxygen content of < 50%, or < 45%, or < 40%, or < 35%, or < 25%, or < 20%, or > 5%, measured by 13C NMR spectral integration or elemental analysis.

[0052] The cyclic polyol is commercially available from petrochemical or bio-based sources. In embodiments, the cyclic polyols useful for preparing the rosin ester are derived from renewable carbohydrate or lignocellulosic feedstocks. For example, inositol can be obtained by extraction and crystallization from corn steep liquor or other cereal processing streams. Dianhydrohexitols (isosorbide, isomannide, isoidide) are obtained by catalytic double-dehydration of sorbitol, mannitol, or iditol, which themselves are produced by hydrogenation of glucose or fructose. Quinic acid and shikimic acid are naturally occurring cyclic polyols isolated from plant sources such as cinchona bark, conifers, or star anise. Phloroglucinol can be obtained via microbial fermentation of sugars or through valorization of lignin-derived aromatics. 2,5-Bis(hydroxymethyl)furan (BHMF) can be prepared by reduction of 5-hydroxymethylfurfural (HMF), which is derived from dehydration of hexose sugars such as glucose or fructose. Accordingly, the rosin ester can be produced substantially from renewable resources.

[0053] In embodiments, the cyclic polyol is added in amounts of 7 - 85, or 10 - 45, or 40 - 80, or 25 - 65 wt.% to prepare the rosin ester, base total weight of the reactants.

[0054] Optional Carboxylic Acids: In embodiments, the reaction forming the rosin ester further comprises at least one carboxylic acid. Carboxylic acid can be selected from monocarboxylic acid, dicarboxylic acid, polycarboxylic acid, and mixtures thereof.

[0055] Examples of carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, cerotic acid, benzoic acid, phenylacetic acid, cyclopropanecarboxylic acid, cyclopentanecarboxylicacid, cyclohexanecarboxylic acid, linoleic acid, alpha-linolenic acid, elaidic acid, sapienic acid, arachidonic acid, myristoleic acid, palmitoleic acid, oleic acid, myristic acid, isostearic acid, tall oil fatty acid, adipic acid, 3 -methyladipic acid, succinic acid, sebacic acid, 1,4- cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2- cyclohexanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3- cyclopentanedicarboxylic acid, isophthalic acid, terephthalic acid, phthalic acid, TOFA dimer, hydrogenated TOFA dimer, 2-(2-carboxyphenyl) benzoic acid, 2,5-furandicarboxylic acid, camphoric acid, cis-norbornene-endo-2,3-dicarboxylic acid, trimellitic acid, 2,6- naphthalenedicarboxylic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, brassylic acid, dodecanedioic acid, thapsic acid, trimesic acid, and mixtures thereof.

[0056] In embodiments, the carboxylic acid, if added, is present in an amount of 15- 75 wt.% based on the total weight of the reactants, such as 30-70 wt.%, 40-65 wt.%, 20-50 wt.%, 6-40 wt.%, 7-30 wt.%, or 8-22 wt.%. In particular embodiments, a dicarboxylic acid (e.g., adipic acid, succinic acid, sebacic acid, phthalic acid) is used at 5-25 wt.% to adjust molecular weight, softening point, and compatibility; a monocarboxylic acid (e.g., stearic acid, benzoic acid, tall oil fatty acid) is used at 0.5-5 wt.% as a chain-stopper to control hydroxyl number and limit branching; and a poly carboxylic acid (e.g., trimellitic acid, trimesic acid) is used at 0.5-8 wt.% to introduce limited branching while avoiding gelation.

[0057] Characteristics / Properties of Rosin Esters: In embodiments, the rosin ester as formed comprises cyclic carbons in an amount of 50-98%, such as 55-95%, 60-90%, or 65- 95%, or more generally greater than 60% and up to 100%, based on the total carbon atoms present, as determined by 13C nuclear magnetic resonance (13C NMR) spectroscopy.

[0058] In embodiments, the rosin ester as formed has a weight-average molecular weight of 300-7000 g / mol, such as 1500-6000 g / mol, or 2000-5000 g / mol, and in further embodiments less than 6000, 5500, 5000, 4000, 3000, or 2000 g / mol, as determined by gel permeation chromatography (GPC).

[0059] In embodiments wherein the rosin feedstock is unhydrogenated or fraction- enriched, the rosin ester has a dehydroabietic acid (DHA) content greater than 35 wt.%, such as 35-65 wt.% or 38-55 wt.%, based on the total weight of the rosin ester.

[0060] n embodiments wherein the rosin feedstock is hydrogenated, the rosin ester has a DHA content less than 35 wt.%, such as less than 30 wt.% or 10-30 wt.%.

[0061] In embodiments, the rosin ester has a Gardner color of < 3, or < 2, or < 1, or > 0.001, measured according to ASTM DI 544-04 (2010).

[0062] In embodiments, the rosin ester has a hydroxyl number of < 50, or < 40, or < 30, or < 20, or < 10, or < 6, or < 3 mg / KOH / g, measured according to ASTM E222.

[0063] In embodiments, the rosin ester has an acid number of < 50, or < 40, or < 30, or < 20, or < 15, or < 10, or < 5 mg / KOH / g, measured according to ASTM D465.

[0064] In embodiments, the rosin ester has a glass transition temperature (Tg) of -80 to 100°C, or -40 to 80°C, or -30 to 80°C, or 0 to 70°C, or 20-60 °C, as determined by differential scanning calorimetry (DSC) according to ASTM D6604.

[0065] In embodiments, the rosin ester has a softening point of 0 - 150°C, or 50 - 130°C, or 70 - 120°C, measured by the Ring-and-Ball method according to ASTM E28.

[0066] In embodiments, the rosin ester has an oxygen content of 2-15%, or < 10%, or < 8%, or < 6%, or 2 - 15%, or 3 - 12%, or 2 - 10%, or 3 - 7%, or > 2%, or < 9%, as determined by 13C NMR spectroscopy or elemental analysis.

[0067] In embodiments, the rosin ester resin has a melt viscosity at 150°C of 12000 to 15000 mPa-s; or > 12500 mPa-s; or < 14500 mPa-s, or 10,000-20,000 mPa s, measured with a Brookfield RTV viscometer using a spindle rotation speed of 3 rpm at 150°C.

[0068] In an embodiment, the rosin ester resin has a refractive index > 1.52, or > 1.55, measured at 20 °C using an Abbe refractometer according to ASTM D1218, and a Brookfield viscosity of 50 to 25,000 mPa s at 177°C measured at 3 rpm per ASTM D 3236.

[0069] In embodiments with renewable polyol feedstock, the rosin esters made therefrom are characterized as having high renewable carbon content. The rosin ester includes at least 80%, at least 85%, at least 90%, or at least 95% biogenic carbon, as determined according to ASTM D6866 (New Carbon Content test method). Such levels demonstrate that the compositions are derived substantially from renewable resources, while also providing compatibility and performance properties comparable to conventional petroleum-derived tackifier.

[0070] (Rosin Ester-based Composition): The rosin ester is additionally characterized as being compatible with a number of polymers, forming a rosin ester-based composition useful, for example, as a tackifier in adhesives, sealants, elastomers, tire compounds, and related applications. The compatibility is determined by the Compatibility Test Method for phase separation, or by the cloud point in the Cloud Point Compatibility Test Method.

[0071] In embodiments, the rosin ester shows compatibility with polymers including ethylene vinyl acetate (EVA), metallocene polyolefins (mPOE), functional polyolefins, amorphous a-olefins (APO), styrenic block copolymers, polybutadiene polymers, polylacticacid polymers, polyesters, thermoplastic polyurethanes, acrylates, polyhydroxyalkanoates, and mixtures thereof.

[0072] In embodiments in blends with polymers as determined by the Cloud Point Compatibility Test Method, the rosin ester exhibit cloud points consistent with good tackifier solubility under the stated test condition. In embodiments, a homogeneous 1 : 1 (w / w) melt of the rosin ester and the polymer, prepared at 180-200 °C with agitation, exhibits a cloud point upon cooling (-2 °C / min) of less than 150 °C, such as 40-140 °C, at an optical transmission threshold of 80% T. Lower cloud points indicate greater compatibility for a given polymer- resin pair.

[0073] In embodiments, the rosin ester in a 1 : 1 (w / w) blend with ethylene-vinyl acetate (EVA) copolymers for EVA grades containing -18-33 wt.% vinyl acetate exhibits a cloud point (80% T criterion) about 80-140 °C; the blend exhibits a cloud point of about 40- 110 °C in a 1 : 1 (w / w) blend with metallocene-catalyzed poly-a-olefins (mPO; e.g., ethylene / 1 -octene elastomers); and the blend exhibits a cloud point of about 70-120 °C in a 1 : 1 (w / w) blend with amorphous poly-a-olefins (APAO).

[0074] In embodiments, the use of hydrogenated rosin feedstock lowers the cloud point of the polymer / rosin-ester blend relative to the corresponding ester prepared from unhydrogenated rosin, typically by about 20-60 °C for EVA, mPO, and APAO systems under the stated test conditions. Without being bound by theory, this improvement is attributed to the reduced aromaticity / unsaturation (lower DHA fraction) and associated shift in solubility parameter imparted by hydrogenation of the rosin moiety.

[0075] In embodiments, compatible polymer / tackifier ratios include 60 / 40, 55 / 45, and 50 / 50 (w / w) polymer / rosin-ester at processing temperatures of 100-200 °C, with the blends remaining substantially free of visible phase separation by the Compatibility Test Method and exhibiting cloud points within the ranges recited herein by the Cloud Point Compatibility Test Method.

[0076] In embodiments, the compatible polymer is an ethylene-vinyl acetate copolymer (EVA). Useful EVA copolymers include those having a vinyl acetate content greater than 24 wt.%, or greater than 28 wt.%, or in the range of 25 - 55 wt.%, based on total weight of the copolymer.

[0077] In embodiments, the compatible polymer is metallocene catalyzed polyolefins (mPO). The mPO is selected from the group consisting of a metallocene-catalyzed polyolefin elastomer (mPOE), a metallocene-catalyzed polyolefin plastomer (mPOP), and mixtures thereof. In embodiments, the mPO is a copolymer of ethylene and at least one C3-C20 a-olefin, and contains ethylene in amounts of > 50, or > 60, or > 70, or > 80, or > 90, or < 95 wt.%, based on total weight of the copolymer. Examples of C3-C20 a-olefin include propylene, isobutylene, 1 -butene, 1 -hexene, 1 -pentene, 4-m ethyl- 1 -pentene, 1 -heptene, 1- octene, 1 -nonene, 1 -decene, 1 -dodecene, 1 -tetradecene, 1 -hexadecene, 1 -octadecene, 1- eicosene, and mixtures thereof. Examples of mPO include ethylene / butene copolymers, ethylene / hexene- 1 copolymers, ethylene / octene copolymers, ethylene / a-olefin / diene modified interpolymers (e.g., ethylene / propylene / diene modified interpolymers, ethylene / propylene / octene terpolymers, etc.), ethylene / propylene copolymer, propylene / 1 -butene copolymers, propylene / 1 -hexene copolymers, propylene / 4-methyl-l -pentene copolymers, propylene / 1 -octene copolymers, propylene / ethylene / 1 -butene copolymers, propylene / ethylene / ethylidene norbornene copolymers, propylene / ethylene / 1 -hexene copolymers, propylene / ethylene / 1 -octene copolymers, propylene / styrene copolymers, and propylene / ethylene / styrene copolymers. In embodiments, the mPO further comprises C4-C18 diolefin and / or alkenylbenzene.

[0078] In embodiments the compatible polymer is amorphous polyolefin (APO). APO is used instead of or in addition to the mPO. The APO is a polymer derived from the polymerization of a-olefins, e.g., ethylene, propylene, butene, etc. In embodiments, the APO is characterized by its amorphous (non-crystalline) structure, with molecular chains being arranged randomly rather than in a highly ordered pattern. In embodiments, the APO is selected from the group consisting of polyethylene (PE); polypropylene (PP); polybutylene (PB); copolymers of propylene and ethylene; copolymers of propylene and 1 -butene or other higher a-olefins; terpolymers of ethylene, propylene, and 1 -butene; ethyl ene-propylene rubber; and mixtures thereof. In embodiments, the APO comprises propylene-based polymers selected from any of linear propylene homopolymers and propylene copolymers. Propylene-based polymers can have a propylene content of at least 50% and can be produced using Ziegler-Natta or metallocene catalysts.

[0079] Examples of rosin ester-based formulations incorporating the rosin ester include hot-melt adhesive formulations, wherein the compatible polymer is added in amounts of 10-90 wt.% (e.g., 50-80 wt.% EVA, mPO, or APO), the rosin ester is added in amounts of 20-50 wt.%, and up to 50 wt.% of at least one additive (e.g., wax, plasticizer, stabilizer) is included.

[0080] Other rosin ester-based formulations include tire and rubber compounds. For example, a formulation containing: (i) a rubber component comprising at least one diene elastomer and based on 100 parts by weight (phr) of the rubber component: a) 5-75 phr of therosin ester as tackifying agent; (ii) 30-200 phr of a filler; (iii) 0-50 phr of a plasticizer; and (iv) 0-90 phr of an optional additive. The rubber component may include natural rubber, synthetic polyisoprene, polybutadiene, styrene-butadiene rubber, or copolymers thereof.

[0081] In embodiments, the rosin ester is employed in pressure-sensitive adhesives (PSAs), wherein the composition comprises 10-60 wt.% of the rosin ester in combination with 10-40 wt.% of one or more polymers, e.g., a polyolefin, and styrene block copolymers (e.g., styrene-isoprene-styrene or styrene-ethylene-butylene-styrene) and 10-40 wt.% a plasticizer, optionally with further resins, oils, and stabilizers. The PSA formulations can be applied to tapes, labels, or hygiene articles. Adhesive performance may be characterized according to PSTC or FINAT methods, including 180° peel strength, loop tack, and shear holding power. For example, representative PSA compositions including the rosin esters of the present invention may exhibit peel strengths of at least 5 N / 25 mm and shear holding power of at least 1000 minutes at 23 °C.

[0082] In embodiments, the rosin ester is incorporated in sealants or construction adhesives, comprising 5-40 wt.% rosin ester, 30-70 wt.% polymer such as EVA or polyolefin, 10-60 wt.% filler, and 0-20 wt.% of a plasticizer such as wax or oil.

[0083] In embodiments, the rosin ester is blended with bioplastics, such as polylactic acid (PLA), at levels of 10-40 wt.% to improve adhesion, flexibility, and toughness.

[0084] In embodiments, the rosin ester is incorporated into coating compositions, such as varnishes or alkyd-based systems, at 20-60 wt.% together with film-forming polymers and solvents. In embodiments, the rosin ester exhibits melt or solution compatibility with at least one film-forming polymer selected from acrylic or styreneacrylate copolymers, vinyl polymers including polyvinyl acetate and polyvinyl butyral, alkyd resins, and saturated or unsaturated polyesters; and in further embodiments is blendable with polyurethane, phenolic, epoxy, or cellulose-based systems under customary solvent or meltmixing conditions.

[0085] Examples of fillers include calcium carbonate, carbon nanotube, clay, mica, silica, silicates, talc, titanium dioxide, alumina, zinc oxide, starch, wood flour, carbon black, and mixtures thereof. Examples of plasticizers include aliphatic acid esters, hydrocarbon processing oils, tall oil pitch, modified tall oil pitch, and mixtures thereof. Examples of additives include activators, curing agents, stabilizers, neutralizing agents, thickeners, coalescing agents, slip agents, release agents, antimicrobial agents, surfactants, flame retardants, antioxidants, antiozonants, color change pH indicators, plasticizers, film forming additives, dyes, pigments, UV stabilizers, UV absorbers, catalysts, fillers, viscosity modifiers,deaerators, toughening agents, adhesion promoters, colorants, heat stabilizers, lubricants, flow modifiers, drip retardants, antiblocking agents, antistatic agents, wax, processing aids, and stress-relief additives.

[0086] Rosin ester-based compositions may be prepared by conventional blending methods. In embodiments, the rosin ester and polymer are combined in a heated vessel, extruder, or internal mixer at 100-200 °C until homogeneous, with fillers, waxes, oils, or stabilizers incorporated under shear. The homogeneous mixture is discharged and processed into pellets, sheets, or applied directly as a hot-melt adhesive, compounded rubber, sealant, or coating composition.

[0087] Properties of Rosin-Ester Based Composition: When used as a tackifier in formulations, the rosin ester is highly compatible with a number of polymers, to produce stable, smooth, and clear compositions wherein phase separation does not occur. The rosin ester-based composition also provides lower melt viscosities, higher specific adhesion properties, and better heat resistance.

[0088] In embodiments, a hot-melt adhesive composition containing the rosin ester as tackifier has a Brookfield viscosity of 500-20,000 mPa s, or 800-15,000 mPa s, or 1, GOO- 12, 000 mPa s, measured at 160 °C in accordance with ASTM D3236.

[0089] In embodiments, the hot-melt adhesive composition exhibits peel strength of > 1.5 N / cm, > 2.0 N / cm, or > 2.5 N / cm, measured on polyethylene or polypropylene film substrates according to ASTM D903. Shear adhesion failure temperature (SAFT) is >70 °C, >80 °C, or >90 °C, measured by bonding Kraft paper strips and loading under shear until bond failure occurs.

[0090] In embodiments, the hot-melt adhesive composition exhibits a peel adhesion failure temperature (PAFT) of >50 °C, >60 °C, or >70 °C, measured according to ASTM D4498. The adhesive maintains cohesive integrity and bond strength at elevated service temperatures, reflecting the contribution of the cyclic polyol-rosin ester to thermal stability.

[0091] In embodiments, a hot-melt adhesive composition containing the rosin ester exhibits at least 20 %, or at least 50%, or at least 90% biodegradation at 60 days when tested according to ASTM D5338-15 (“Biodegradation Test Method”).

[0092] Preparation of Rosin Esters: The rosin ester can be prepared by methods as described in U.S. Patent No. 11034858, incorporated herein by reference.

[0093] In embodiments, the rosin ester is prepared reacting the rosin, the cyclic polyol, optionally a carboxylic acid, and optionally in the presence of an esterification catalyst, at a temperature ranging from 150 - 300°C for 2 - 18 hours, typically withcontinuous removal of water under reduced pressure or using an azeotropic solvent, to drive the esterification to completion. In embodiments, the rosin ester is obtained as a viscous liquid or soft solid at 20 °C and 1 atm pressure.

[0094] Suitable esterification catalysts include Lewis acids and Bronsted-Lowry acids. Examples include acetic acid, p-toluenesulfonic acid, methanesulfonic acid, hypophosphorous acid, boric acid, sulfuric acid, triphenylphosphite, calcium hydroxide, cation exchange resins, SiCh-supported and AhCh-supported metal oxides, calcium oxide, magnesium oxide, zinc oxide, aluminum oxide, iron chloride, calcium formate, calcium phosphonates, and mixtures thereof.

[0095] In embodiments, a co-catalyst is used in the esterification reaction. Examples of the co-catalyst include acridone, anthrone, 9-fluorenone, thioxanthone, xanthone, derivatives, and combinations thereof.

[0096] A disproportionation catalyst, also referred to as a rosin stabilizer, can be included in the esterification reaction. The disproportionation catalyst can be selected from 2,2'thiobisphenols, 3,3 '-thiobisphenols, 4,4'-thiobis(resorcinol), l,l'-thiobis(pyrogallol), 4,4'- thiobis(6-t-butyl-m-cresol), 4,4'-thiobis(6-t-butyl-o-cresol), thiobisnaphthols, 2,2'-thio- bisphenols, 3,3 '-thio-bis phenols, palladium, nickel, platinum, Pd / C, iodine, iodides, sulfides, poly-t-butylphenoldisulfide, 4,4'thiobis(2-t-butyl-5-methylphenol, nonylphenol disulfide oligomers, amylphenol disulfide polymer, and mixtures thereof.

[0097] In embodiments, the rosin ester undergoes secondary processing such as hydrogenation and / or disproportionation, which reduces the dehydroabietic acid (DHA) content, for example to < 35 wt,% or < 30 wt.%. In other embodiments, the secondary processing is dehydrogenation or oxidation, which increases the DHA fraction or generates DHA-like aromatic structures. In yet other embodiments, the rosin ester is used without secondary processing, while still providing compatibility with polymers including, but not limited to, ethylene-vinyl acetate (EVA), metallocene polyolefins, amorphous poly-a-olefins (APAO), styrenic block copolymers, and related elastomeric or thermoplastic polymers.

[0098] Applications: The rosin ester composition, due to the compatibility with a number of polymers when used as a tackifier, shows improved adhesion to a broad range of adherends from low polar to highly polar adherends, as well as to highly smooth substrates, e.g., film, paper, etc. The rosin ester can be used in packaging, bookbinding, labeling, tapes, labels and stickers, protective films, sealants, diapers and sanitary pads, edge banding, shoe soles, leather goods, electronic assembly, protective coating, trim and panel bonding, headliners, interlining, etc.

[0099] As tackifying agent, the rosin ester can be used in hot-melt and pressuresensitive adhesives, adhesive dispersions such as adhesive aqueous dispersions, modifiers for rubbers and various plastics, emulsifiers for synthetic rubbers, base materials for chewing gum, resins in coating compositions, inks, sizing agents for paper making, asphalt markings, pavement markings, road surface markings, thermoplastic road surface markings, inks, coatings, rubbers (e.g., tires and tire treads), sealants and plasticizers.

[0100] Hot melt adhesives containing the rosin ester are useful in case and carton sealing, tray forming, and bookbinding applications. In such uses, the compositions are applied in molten form and provide strong bonds over a wide temperature range, including refrigerated and hot-filled conditions. Compositions incorporating the rosin esters described herein can achieve shear adhesion failure temperatures (SAFT) of at least 80 °C, and open times of 20- 120 seconds depending on formulation. The adhesives are particularly suited for packaging substrates such as kraft paper, recycled board, chipboard, coated paperboard, and multilayer laminates including aluminum foil and polymer films.

[0101] Adhesives containing the rosin ester are suitable for use in the manufacture of absorbent articles, such as diapers, training pants, feminine hygiene products, and adult incontinence products. In such applications, the adhesives can be employed as construction adhesives, positioning adhesives, and elastic attachment adhesives. Representative formulations include 20-50 wt.% of the rosin ester tackifier with 50-80 wt.% of a polyolefin or block copolymer base polymer. The adhesives may be applied in fiberized or bead form and provide secure bonding while maintaining softness and flexibility of the article.

[0102] The rosin ester compositions can also be employed in woodworking, furniture, flooring, and panel lamination adhesives. In such applications, the adhesives are typically formulated with polyolefin polymers and waxes to achieve viscosities of 5,000-200,000 mPa- s at 200 °C, suitable for extrusion or roller application. The compositions are capable of bonding wood, engineered wood, particleboard, and composite panels with strong adhesion and resistance to creep at elevated temperature and humidity.

[0103] The rosin ester can also be used in a variety of additional applications, including as a softener and plasticizer in chewing gum bases, as a weighting and clouding agent in beverages, as a surfactant, surface activity modulator, or dispersing agent, as an additive in waxes and wax-based polishes, as a modifier in skin products and cosmetic formulations (e.g., mascara), in the electrical industry as insulators, as drying oils in making paints and other wood treatment products, in treating the hulls of wooden boats, in soaps, in candles, as a lubricant in automotive applications and engine lubricants, to make biodiesel, to produce biodegradablehydraulic fluids, in metal working and other industrial applications, as a phase change material, or a curing agent in concrete.

[0104] (Analytical Methods): The rosin ester described herein is characterized as having a unique combination of identifiable characteristics and properties. The identity of the cyclic polyol incorporated in the rosin ester is confirmed by the presence of corresponding ester linkages formed between the carboxyl groups of the rosin acids and the hydroxyl groups of the cyclic polyol, as determined by FTIR spectroscopy (appearance of carbonyl ester absorption at -1735 cm ') and optionally supported by 1H and 13C NMR spectroscopy.

[0105] The content of dehydroabietic acid in the rosin ester is determined by gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography (HPLC) following alkaline hydrolysis of the ester to release rosin acid constituents. DHA is quantified by comparison against authentic standards, and the weight percentage of DHA is reported relative to the total weight of rosin acid components detected.

[0106] The acid number of the rosin ester can be determined in accordance with ASTM D465. Results are reported in milligrams (mg) of potassium hydroxide (KOH) required to neutralize the acidic constituents in one gram (g) of sample.

[0107] The weight average molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (PDI) of the rosin ester can be determined by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the eluent at 30 °C, calibrated with narrow molecular weight distribution polystyrene standards. Values are reported in grams per mole (g / mol).

[0108] The glass transition temperature of the rosin ester can be determined according to ASTM D6604, or by differential scanning calorimetry (DSC) following ASTM D3418. Tg is reported as the midpoint of the transition in degrees Celsius (°C).

[0109] When relevant, the percentage of renewable (biogenic) carbon in the rosin ester is determined according to ASTM D6866. Results are reported as percent biogenic carbon relative to total carbon content.

[0110] When the rosin ester is incorporated into end-use applications, e.g., hot-melt adhesives, tires, etc., compatibility with the polymer can be determined via Compatibility test methods previously described.

[0111] The identity of the polymer present in formulations containing the rosin ester can be determined by spectroscopic and thermal analytical techniques. Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR, 1H and 13C) provide characteristic signals that distinguish ethylene-vinyl acetate (EVA), amorphous poly-a-olefins (APO), styrenic block copolymers (SBCs), and polyester-based polymers such as polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) may also be used to distinguish polymers based on glass transition temperatures (Tg), melting points, and thermal degradation profiles.

[0112] The relative amounts of polymer and rosin ester can be determined by solvent extraction, followed by analysis of the isolated polymer fraction using FTIR, NMR, DSC, or GPC. Together, these techniques permit reliable identification of the polymer(s) present in the composition, as well as their relative weight percentages..

[0113] Where relevant, adhesive performance of hot melt adhesive compositions containing the rosin ester can be evaluated according to ASTM DI 876. Results are reported as average peel strength in Newtons per centimeter (N / cm).

[0114] Examples: The following illustrative examples are non-limiting. The components used in the examples include:

[0115] RAI is a tail-oil rosin product from Kraton Corporation having an acid number of - 179 mg KOH / g. Tail-oil rosin products of this type typically exhibit a softening point (Ring & Ball) of 70-80 °C, a Gardner color of 5-10, and a specific gravity of 1.05— 1.10. The molecular weight (Mw) is in the range of 200-400 Da. The apparent glass transition temperature (Tg) is sub-ambient or slightly above ambient (10 - 40 °C) as determined by DSC.

[0116] RA2 is a tail-oil rosin product from Kraton Corporation with acid number in the range of 150-180 mg KOH / g, softening point (Ring & Ball) of 60-80 °C, Gardner color in the range of 5-8, specific gravity of 1.05-1.10. The molecular weight (Mw) is in the range of 200-400 Da. The glass transition temperature (Tg) is sub-ambient or slightly above ambient (10 to 40 °C).

[0117] RA3 is a hydrogenated rosin product derived from gum rosin that has undergone catalytic hydrogenation to reduce the level of conjugated double bonds, resulting in improved stability compared to unmodified rosin, having an acid number in the range of 160-175 mg KOH / g, a Ring-and-Ball softening point of 60-70 °C, and a Gardner color of 1- 3. The molecular weight (Mw) is generally in the range of 200- 400 Da with a broad distribution, and the glass transition temperature (Tg) is approximately 10 to 40 °C.

[0118] Antioxidant 1 is a sterically hindered phenolic antioxidant.

[0119] Antioxidant 2 or pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4- hydroxyphenyl)propionate] (CAS 6683-19-8) is a high-molecular weight, sterically hindered phenolic antioxidant used as a primary antioxidant.

[0120] Stabilizer 1 is a polymeric disulfide derived from tert-butylphenol and functions as a radical scavenger and sulfur donor.

[0121] Stabilizer 2 is a phenolic antioxidant stabilizer, chemically 4,4'-thiobis(2-tert- butyl-5-methylphenol) (CAS No. 96-69-5), with the molecular formula C22H3OO2S, and has a melting point of about 170-180 °C.

[0122] mPoE 1950 is an ethylene-a-olefin random copolymer (ethylene-octene) with low polarity, having a density of about 0.874 g / cm3, a Tg of about -56 °C, melting point of about 70 °C, Brookfield viscosity at -177 °C of about 17,000 mPa s, volatile content <0.15 %, tensile strength at break around 1.7-2.0 MPa, elongation at break -190 %, and light Gardner color (-1-2).

[0123] EVA 33.400 is an ethylene-vinyl acetate (EVA) copolymer containing -33 wt.% vinyl acetate and having a high melt flow index (-400 g / 10 min). This polymer is relatively polar and generally shows good compatibility with rosin esters.

[0124] EVA 28.420 is an EVA copolymer with -28 wt.% vinyl acetate and a melt flow index of -420 g / 10 min.

[0125] EVA 18.500 is an EVA copolymer with -18 wt.% vinyl acetate and a melt flow index of -500 g / 10 min. The lower VA content makes this grade less polar and more difficult to compatibilize.

[0126] SBC-1 is a linear triblock copolymer based on styrene and isoprene having a configuration of S-I-S with a polystyrene content of 15%, MFR of 8.5-18.5 g / 10 min at 200°C and 5000g load (ASTM D1238).

[0127] Wax-1 is a microcrystalline wax (highly branched saturated hydrocarbons, C30-C60 range), having a melting point of 88-91°C, an oil content of -0.5 wt.%, a density of 0.92-0.94 g / cm3, and a viscosity of 8-10 mm2 / s at 100°C.

[0128] Cyclic polyols for use in the Examples are shown in Table 1 below. “RB” refers to Rotatable C-C Bonds.

[0129] Table 1

[0130] Cloud Point Measurement: Sample compatibility was assessed by a turbidimetry method (to get the cloud point). Turbidimetry equipment (CHEMOTRONIC High Vise Automatic Turbidimetry Analyzer) equipment from Novomatics GmbH, Germany, was applied. The samples were heated to 230°C by the CHEMOTRONIC device and subsequently cooled to 20°C. The turbidity is detected by the absorption due to suspended particles in the liquid and can be associated to the cloud point and qualitatively to a degree of incompatibility. The degree of light transmission through the rosin ester-based composition sample versus temperature was measured across a temperature range of 20°C to 230°C. The light transmission is given as % transmitted light and the temperature is provided as °C. A lower light transmission percentage relates to a higher degree of turbidity and thereby served as an indicator for a higher cloud point temperature and a lower degree of compatibility of the measured material blend at a given temperature value, or across a given temperature range.

[0131] Example RE-1 - Tricyclodecane Dimethanol (TCDM) Rosin Ester: 600 g rosin RA-1 was charged into a 1 L four-neck flask under nitrogen and heated to 200 °C until fully molten with mechanical stirring. Tricyclodecanedimethanol (170 g), Antioxidant 1 (0.2 wt%) and Stabilizer 1 (0.3 wt%) were added. The reaction mixture was heated to 280 °C (30 °C / h) and held at 280 °C for 9 hours with water removal. Volatiles were stripped off during a 2 h nitrogen sparge, the mixture was cooled to 180 °C, and discharged. The obtained product had a softening point of 73 °C and an acid value of 4.6 mg KOH / g. The DHA content of the product was not measured. Based on the use of a DHA-enriched rosin feed and the absence of hydrogenation in the esterification procedure, the DHA content is expected to be about 35-50 wt.% of the rosin ester. The weight average molecular weight was not measured, but expected to be in the range of 600-900 g / mol. The Tg is expected to be 40 °C.

[0132] A 50:50 (w / w) blend of the rosin ester with mPoE 1950 was prepared and tested for cloud point using a Novomatics Cloudpoint Machine. A cloud point temperature of 100 °C was recorded at 80% transmission.

[0133] Example RE-l-HR - Tricyclodecane Dimethanol (TCDM) Rosin Ester (Hydrogenated Rosin Feed). Example RE-1 was repeated but with 600 g of hydrogenated rosin RA-3. The obtained product had a softening point of 87 °C and an acid value of 0.4 mg KOH / g. The DHA content of the product was not measured, but expected to be about <= 30wt.% of the rosin ester The weight average molecular weight was not measured, but expected to be in the range of 600-900 g / mol. The Tg is expected to be about 40 °C.

[0134] A 50:50 (w / w) blend with mPoE 1950 showed a cloud point of 50 °C at 80% transmission.

[0135] Example RE-2 - 1,4-Cyclohexane Dimethanol (CHDM) Rosin Ester. Example RE-1 was repeated but with 125 g of 1,4-cyclohexane dimethanol. The obtained product had a softening point of 62 °C and an acid value of 1.4 mg KOH / g. The DHA content of the product was not measured but is expected to be about 35-45 wt.% of the rosin ester. The average molecular weight was not measured, but expected to be in the range of 600-900 g / mol. The Tg is expected to be about 20 °C.

[0136] A 50:50 (w / w) blend with mPoE 1950 showed a cloud point of 136 °C at 50% transmission.

[0137] Comparative Example RE- 16 - Pentaerythritol Rosin Ester. Example RE- 1 was repeated except that 200 g of pentaerythritol was used as the polyol. The resulting resin has an acid number of about 5 mg KOH / g, a Tg of about 52 °C, a softening point of 96-103 °C. The DHA content of the products was not measured but based on the use of a tail-oil rosin feed and the absence of hydrogenation in the esterification procedure, the DHA content is expected to be about 35-50 wt.% of the rosin ester.

[0138] When blended 1 : 1 with mPoE 1950, the product exhibited a cloud point of > 200 °C (80% transmission), indicating poor compatibility.

[0139] Comparative Example C-l - Pentaerythritol Rosin Ester. 1400.5 g of rosin acid RA2 was reacted with 161.2 g of pentaerythritol under standard esterification conditions. The product had a softening point of 90.7 °C, an acid number of 6.7 mg KOH / g, and a Gardner color of 4.0. The DHA content of the product was not measured but is expected to be about 35-45 wt.% of the rosin ester.

[0140] Example C-2 - Isosorbide Rosin Ester. A repeat of Example C-l but with 346.2 g of isosorbide as the polyol. The product had a softening point of 62.6 °C, an acid number of 15.6 mg KOH / g, and a Gardner color of 9.3. The DHA content of the product was not measured but is expected to be about 40-50 wt.% of the rosin ester.

[0141] Example C-3 - Isosorbide Rosin Ester (Repeat Run), A repeat of Comparative Example C-2 was carried out with similar conditions. The product had a softening point of 69.3 °C, an acid number of 11.4 mg KOH / g, and a Gardner color of 10.3. The DHA content of the product was not measured but is expected to be about 40-50 wt.% of the rosin ester.

[0142] Example C-4 - Isosorbide Rosin Ester with Fumaric Acid Fortification. A rosin ester was prepared under conditions generally similar to Comparative Example C-2, except that 36.4 g of fumaric acid (2 wt.% based on rosin) was added to 1400.6 g of rosin acid and 1.4 g of Stabilizer 2 at 180 °C and held for 1 h prior to addition of 346.3 g of isosorbide. The mixture was heated to 270 °C, and 3.7 g of hypophosphorous acid was added in three equal portions. The mixture was maintained at 270 °C for 14.75 h, followed by steam sparging for 3 h. After neutralization with 1.8 g of KOH, the product was cooled and discharged. The obtained rosin ester had a softening point of 77.4 °C, an acid number of 12.4 mg KOH / g, and a Gardner color of 9.4. The DHA content of the product was not measured but is expected to be about 40-50 wt.% of the rosin ester.

[0143] Example C-5 - Isosorbide Rosin Ester with Double Catalyst Charge. A rosin ester was prepared under conditions generally similar to Comparative Example C-2, except that in addition to the initial 3.6 g of hypophosphorous acid charged in three equal portions, an additional 3.6 g was introduced in three further batches at 6 h, 10 h, and 11 h while at 270 °C. The total reaction time at 270 °C was approximately 15 h, followed by steam sparging for 2 h. The mixture was neutralized with 1.8 g KOH at 230 °C and discharged. The product had an acid number of 13.8 mg KOH / g, a softening point of 69.8 °C, and a Gardner color of 9.4. The DHA content was not measured but is expected to be about 40-50 wt.% of the rosin ester.

[0144] Compatibility Testing of Isosorbide Rosin Esters. The rosin esters from Comparative Example C-l, and C-2 through C-5 were blended with polymers at 1 : 1 weight ratios and evaluated by the cloud point (CP) test. Blends were heated until homogeneous and then cooled, and the CP was defined as the temperature at which haze first appeared. The results are summarized in Table 2 below.

[0145] Table 2: Cloud Point (°C) Compatibility Testing

[0146] In addition, the rosin esters were found to blend homogeneously with natural rubber and styrenic block copolymer (SBC-1) under the same test conditions.

[0147] End-Use Application as Tackifiers: Hot-melt adhesive formulations were prepared using the following rosin esters as tackifiers: C-l (pentaerythritol ester), C-2(isosorbide ester), C-3 (isosorbide ester, repeat run), and C-4 (isosorbide ester fortified with 2 wt.% fumaric acid).

[0148] Each adhesive formulation contained 103.2 g tackifier resin, 30.0 g EVA 28.150, 90.0 g EVA 28.420, 75.0 g Wax-1, and 1.0 g Antioxidant 2. Specimens were conditioned at the indicated temperatures, pressed together under controlled conditions, and peeled to evaluate fiber tear. Adhesion is reported as fiber tear percentage (%FT) on virgin “Natronkraff ’ cardboard. The procedure is substantially in accordance with ASTM D903 (180° peel), except that the measured result is recorded as % fiber tear instead of peel force. Unless otherwise specified: specimens are 25 mm * 150 mm; an adhesive film (~25 ± 5 g / m2) is applied, a 25 mm overlap is pressed at 0.2-0.4 MPa for 5-10 s; bonded specimens are conditioned at the indicated test temperature (-40 to 70 °C) for >15 min; joints are peeled at -180° and the percent area exhibiting fiber tear is recorded as %FT (average of >3 replicates).

[0149] Fiber tear percentages at temperatures from -40 °C to 70 °C are summarized in Table 3.

[0150] Table 3: Fiber Tear (%) vs. Temperature Data

Claims

CLAIMS1. A rosin ester comprising the reaction product of a rosin with one or more cyclic polyols represented by any of general formula (I), general formula (II), general formula (III), general formula (IV) or a mixture thereof:wherein,3 < n < 18,each of R1-R8 is independently selected from hydrogen, hydroxyl (-OH), hydroxymethyl (-CH2OH), and carboxyl (-COOH), with each of R7-R8 is independently oriented a or P, at least two of R1-R8 are substituents other than hydrogen, at least one of R1-R6 is -OH or -COOH, when n =3, each of R’3 and R” is independently hydrogen or methyl, and when n = 4, R’3 is hydrogen, wherein the cyclic polyols are carbocyclic or heterocyclic, aromatic or non-aromatic, the cyclic polyols have: a carbon-to-oxygen atom ratio of 1.0 - 20; a number of rotatable carbon-carbon bonds of < 5, preferably < 3, most preferably < 2; and wherein the rosin ester has an acid number of < 50 mg / KOH / g, preferably < 40 mg / KOH / g; more preferably < 30 mg / KOH / g, measured in accordance with ASTM D465; a weight average molecular weight of < 6,000 g / mol, preferably < 5000 g / mol, more preferably < 4000g / mol; and a glass transition temperature (Tg) of -40 to 100°C measured according to ASTM D 6604.

2. The rosin ester of claim 1, wherein the cyclic polyol is selected from the group consisting of: tricyclodecane dimethanol, cyclohexane dimethanol, a dianhydrohexitol, cyclohexanediol, spiroglycol, phloroglucinol, inositol, quinic acid, and mixtures thereof.

3. The rosin ester of claim 1, wherein at least one of R1-R6 is hydroxymethyl (- CH2OH).

4. The rosin ester of claim 1, wherein all of R1-R6 are hydroxyl (-OH).

5. The rosin ester of claim 1, wherein the cyclic polyol is tri cyclodecanedimethanol with the ratio of number of atoms of carbon to oxygen of 1.5 - 15.

6. The rosin ester of claim 1, wherein the cyclic polyol is cyclohexanedimethanol with the ratio of number of atoms of carbon to oxygen of 1.5 - 12.

7. The rosin ester of claim 1, wherein the cyclic polyol is a dianhydrohexitol selected from the group consisting of isosorbide, isomannide, and isoidide.

8. The rosin ester of claim 1, wherein the cyclic polyol has an average hydroxyl functionality of 2 to 10.

9. The rosin ester of claim 1, wherein the cyclic polyol has a ratio of number of atoms of carbon to oxygen of 2.1 - 7.5.

10. The rosin ester of any of claims 1-9, having: a Gardner color of < 3; a hydroxyl number of < 50 mg KOH / g; a softening point of 70-120 °C; a Brookfield viscosity (ASTM D-3236) of 50 to 25,000 mPa s at 177°C measured using Brookfield Thermosel viscometer spindle SC4-27 at 3 rpm per ASTM D 3236; and an oxygen content of 2-10 wt%.

11. The rosin ester of any of claims 1-10, wherein the rosin ester has a dehydroabietic acid content of > 35 wt.%, based on the total weight of the rosin ester.

12. The rosin ester of any of claims 1-10, wherein the rosin is hydrogenated and the rosin ester has a dehydroabietic acid content of < 35 wt.%.

13. The rosin ester of any of claims 1-12, wherein the rosin ester comprises biogenic carbon of at least 20%, or at least 50%, or at least 80%, as determined according to ASTM D6866.

14. The rosin ester of any of claims 1 - 13 when blended 1 : 1 (w / w) with a polymer selected from the group of ethylene-vinyl acetate copolymers, metallocene-catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a-olefin plastomers, amorphous poly-a-olefins, remains free of visible phase separation after 24 hours at 160 °C in the Compatibility Test Method.

15. The rosin ester of any of claims 1 - 13, when blended 1 : 1 (w / w) with a polymer selected from the group of ethylene-vinyl acetate copolymers, metallocene- catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a-olefin plastomers, amorphous poly-a-olefins, forming a blend exhibiting a cloud point < 150 °C (80 % transmission) in the Cloud Point Compatibility Test Method.

16. The rosin ester of any of claims 1 - 13, when blended 1 : 1 (w / w) with an ethylene-vinyl acetate copolymer containing from 18 to 33 weight percent vinyl acetate, based on the total weight of the copolymer, forming a blend exhibiting a cloud point of < 140 °C (80 % transmission) in the Cloud Point Compatibility Test Method.

17. The rosin ester of any of claims 1 - 13, when blended 1 : 1 (w / w) with a metallocene-catalyzed poly-a-olefin elastomer, forming a blend exhibiting a cloud point of < 110 °C (80 % transmission) in the Cloud Point Compatibility Test Method.

18. The rosin ester of any of claims 1 - 13, when blended 1 : 1 (w / w) with a metallocene-catalyzed poly-a-olefin plastomer, forming a blend exhibiting a cloud point of < 120 °C (80 % transmission) in the Cloud Point Compatibility Test Method.

19. The rosin ester of any of claims 1 - 13, when blended 1 : 1 (w / w) with an amorphous poly-a-olefin, forming a blend exhibiting a cloud point of < 150 °C at 80 % transmission in the Cloud Point Compatibility Test Method.

20. An adhesive composition comprising:10-60 wt.% of a rosin ester according to any one of claims 1-13;20-70 wt.% of a polymer selected from the group consisting of ethylene-vinyl acetate copolymers, metallocene-catalyzed poly-a-olefin elastomers, metallocene-catalyzed poly-a- olefin plastomers, and amorphous poly-a-olefins; and0-40 wt.% of a plasticizer; wherein the adhesive exhibits a cloud point of less than 160 °C determined by theCloud Point Compatibility Test Method, and a melt viscosity at 180 °C of less than 50,000 mPa.s measured by a Brookfield rotational viscometer with Thermosel heater in accordance with ASTM D3236.

21. A pressure-sensitive adhesive composition comprising:10-60 wt.% of a rosin ester according to any one of claims 1-13,10-40 wt.% of a polyolefin or a styrenic block copolymer, and10-40 wt.% of a plasticizer, wherein the adhesive exhibits a 180° peel strength of at least 5 N / 25 mm measured on a stainless-steel substrate at a peel rate of 300 mm / min in accordance with ASTM D3330, and a shear holding power of at least 1000 minutes at 23 °C, determined on a 25 mm x 25 mm overlap bond under a 1 kg load in accordance with ASTM D3654.

22. A tire composition comprising:(i) a rubber component selected from the group consisting of natural rubber, synthetic polyisoprene, polybutadiene, styrene-butadiene rubber, and mixtures thereof, and based on 100 parts of by weight (phr) of the rubber component;(ii) 30 to 200 phr of a filler; and(iii) 5 to 75 phr of a rosin ester according to any one of claims 1-13.

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